Tag Your It
by BloodyEmeraldRose
Summary: Yumiko and Killua have always had a love and hate type of friendship ever since having met at the Hunter Exam. Yet Yumiko could never have guessed that her relationship with Killua could change so drastically after saying one simple word to the assassin. Yandere Killua. Nothing too sexual involved, but rated M just to be safe for some violent scenes.


(A/N: I'd like to think of this as a twisted Valentine's Day story, hee hee~ I've been obsessed with yandere stories lately, so I wanted to try my hand at one. And Killua definitely seems like the type who would snap when it comes to love. ;) Not sure if I made Killua twisted enough while keeping him still like his original character, but I did my best.

I hope everyone who reads this enjoys the story and nothing is too confusing. I'd actually really like to write a more 'normal' story between these two to show how their friendship and eventual relationship does develop, but I don't think I'd have the time. ^_^')

* * *

Soft pants left the lips of a young girl with midnight colored hair as she dug her kunai into the thick bricks of the basement where she had been confined. Most of her weapons had been taken from her, but she had managed to keep this one hidden from him.

 _How did it come to this_? _Sure our relationship has always been a weird one ever since we first met at the Hunter Exams, but I don't understand what caused him to snap like this_ …?

A sudden tingling in the girls lips caused her to pause in her work, and her fingers moved to touch them.

 _That's right_ … _When Killua broke down because he felt like he couldn't do anything for Gon_ , _I held him in my arms and then_ … _kissed him_ she realized, the memory causing her chest to ache, showing she still cared about him despite everything he had done. _It was the first time I'd ever saw him so distressed, and I just wanted to comfort him-to let him know he wasn't alone_ …

She gripped tightly at the dagger in her hand that had begun to shake while her grey orbs grew misty. _Maybe this is all my fault_? _I shouldn't have told him I loved him when he was in such a vulnerable state_ … _And then to tell him what I did after Gon had been saved and they both chose to go their separate ways_ ….

* * *

"What do you mean you're not coming with us, Yumiko?!" Killua gasped out in disbelief, his sky blue eyes growing wide.

The fifteen year old girl before him just smiled faintly while crossing her arms over her chest. "Its just…I've been away from home for such a long time, and I think its time I head back…Plus I'm getting annoyed by all the tear stained letters Hanzo keeps sending me telling me to come back to the village…."

"So? Since when have you ever cared what you're stupid older brother wanted?" Killua scoffed out with a deep frown. "Besides, I thought you said you weren't even sure if you wanted to continue being a ninja? Didn't you want to be a weapon hunter?"

"Well, yeah-"

"Then just tell Hanzo you're going to travel the world with Alluka and me to pursue your goal," Killua cut off in a firm tone.

"I…can't. I've been putting off my duties long enough, and I feel bad that Chieko and Midori get stuck doing all the missions they've been assigned alone because I'm not there," Yumiko admitted, biting her lip since she could swear Killua's eyes seemed to darken when she mentioned her teammates names. "And even if they can be a pain, I miss my family…."

Feeling a tug at the sleeve of the turquoise shirt she wore, Yumiko looked down; her normally indifferent expression softening when seeing little Alluka staring up at her sadly. "Does this mean we won't see you again, sissy?"

Still amazed Alluka had warmed up to her enough to refer to her like she was family, caused Yumiko to feel even more guilty than she already was for leaving the two of them. But she smiled and gently patted the child on her head.

"Of course you'll see me again. Ninja's travel a lot, so we'll probably run into each other. Isn't that right, Kitty Boy~?" Yumiko finished off playfully, knowing how much the nickname she had dubbed the white haired teen with irked him.

She was surprised when Killua didn't insult her back like he normally would, but instead, pulled her close to his form. Her cheeks warmed up from this, but she had to admit the tight grip he had on her hurt just a little and had a possessiveness to it that left her feeling some what unnerved.

"It isn't fair…Blue went with Gon, so why won't you come with me?" he muttered, referring to their other friend they had met at Heaven's Arena. "Your family doesn't even appreciate you. Not the way I…I mean your friends do…."

A small sigh left Yumiko's lips understanding what he meant. Her body was weaker than the other shinobi that resided in her village due to Yumiko inheriting the same illness that had eventually took her mother's life. The doctors managed to cure her unlike her mother…yet it still made it harder for her to sometimes perform, so she always felt that her clan hated her for this reason.

Yet she realized the only reason her father never pushed her like he had Hanzo or never allowed her to go on certain missions that ninjas' her same age were assigned, was because he was afraid of losing her. This was another reason she wanted to return home. After improving her Nen, she wanted to show everyone that she could be strong, and that her family didn't need to worry about her so much.

She managed to squirm out of Killua's hold, placing a very small kiss on his cheek to show she wasn't doing this to hurt him.

"We'd probably end up killing each other if we were together too much," Yumiko mused with a small giggle considering they often fought like a cat and dog. "And once I settle things at home, I'll come find Alluka and you. Promise."

She lightly ruffled Alluka's dark locks, waving at Killua before taking off; not realizing Killua had lowered his head while his hands had clenched tightly at his sides hard enough to draw blood.

"Are you alright, big brother?" Alluka asked with concern, gripping at one of his hands.

Killua blinked a few times, his orbs that were filled with anger softening when he smiled reassuringly at his little sister. "I will be soon. You'd like it if Yumiko was with us all the time, wouldn't you, Alluka?"

Alluka tilted her head innocently before clapping her hands happily. "Uh-huh! Then we can all play together, right?"

"You bet. But it looks like we'll have to postpone our trip for a while," Killua told the blue eyed girl with an apologetic smile. He then pulled out his phone, quickly dialing his home number where a rather sadistic smirk formed on his lips when Zeno answered. "Hey, grandfather. Could you put dad on the phone? I have a proposition for him…."

* * *

Eyes that had once been filled with light at returning home, had dimmed when coming across the gruesome sight that now lay before them.

"How…?" was the only word that managed to escape Yumiko's lips, her body quivering as she was finding it difficult to remain standing.

All of her family lay dead in the large Japanese styled mansion; their blood staining the walls and floor. She couldn't understand it. They were all so strong, so how could they have been taken out this easily?

"Yu…miko…." a voice weakly spoke up, casing the stunned girl to slowly turn where she saw her teammate, Chieko, standing at the sliding screen door and holding onto his side which had been stained red.

"C-Chieko?!" Yumiko cried out, rushing over to catch the light pink haired male before he could fall forward. Anger began to consume her eyes that had once been filled with distraught. "Who did this to you?!"

"Your family…I'm sorry," Chieko wheezed out, gripping onto Yumiko's hand while tears were in his eyes. "M-Midori, Kotaro sensei, and I were the only…the only ones who tried to help…Everyone else was too frightened to fight them…They…killed sensei and Midori too…."

"Who are 'they' Chieko?" Yumiko asked softly in a cracked voice from seeing how much pain her friend and teammate was in. She needed to tend to his wounds, but if the assailant's were still out there, could she even manage to protect the both of them?

Neither one of them noticed the shadow that had entered the room, not until Chieko was violently pulled away from Yumiko before she could react; the poor teen who had been shoved against the wall hacking up a good amount of blood as a hand had been jabbed straight through his chest.

"Don't touch her…."

It felt like she had been slapped. The malicious voice that belonged to the boy who's clothes were stained crimson, couldn't possibly have come from her friend; the one she had come to love.

"Kil…lua…?" Yumiko whispered out, falling to her knees when he ripped Chieko's heart from his body and her friend fell lifelessly to the floor. Tears poured down her pale cheeks while she covered her mouth to stop the bile she felt rising up when Killua threw the organ to the ground and crushed it underneath his shoe like it was a mere cockroach.

"Why are you crying, Yumiko? I did this for you, don't you see?" Killua said in a tender tone, but his normally bright eyes were filled with darkness.

She tensed up when he was suddenly upon her, the hand he used to kill Chieko wrapping around her waist and pulling her close to his form while Killua's other hand ran through her hair.

"None of them really cared about you. Not like I do…Not only did those bastards cause you mental pain, but they made you push yourself where you could have died multiple times," Killua said, his hold tightening on her while his eyes narrowed. "I knew I couldn't take them out on my own, so I made a deal with my father. If they promised to help me take out the Hattori clan, then I'd stay and be the assassin they always wanted me to be…"

"As long as you could remain at the Zoldyck manor with me, that is…Now, they'll never be able to steal you away from me again." Killua trailed off, smiling as he stared into Yumiko's wide, grey orbs."

Yumiko couldn't believe what she was hearing. True she had seen Killua's blood lust come out in full force before, but she never believed he was capable of something this horrible. She thought Killua had wanted to escape from his family business, so why…?

She gritted her teeth, managing to grab one of her kunai's from the pouch at her side where she jabbed it straight into the young assassins's side.

Killua cried out more from shock than pain-not even wincing when he yanked the weapon out of his body. Yet he did feel like someone had just crushed his own heart when Yumiko shoved him away from her; giving him one of the coldest looks he had ever seen the girl wear before she was running from the room, out into the night.

Wiping away the tears that wouldn't seem to stop as she fled through the eerily quiet village, the girl made her way for a nearby forest, deciding maybe she could find a place to hide there at least until daylight.

"Aren't we a little old to be playing tag, Yumiko?" Killua said with a small chuckle when he calmly started to pursue after her, a dark smirk on his face. She was clearly just stunned, but he knew Yumiko would eventually understand he had killed everyone she _thought_ she loved for her sake: for both of theirs.

Darting behind a large tree and trying to steady her beating heart from fear he would be able to hear it, she gripped onto a spiked pink and white fan she normally tended to use as a weapon, not wanting to, but she was prepared to fight Killua. Yet could she _kill_ him if it came to that…?

Hearing the snapping of a branch close by, she quickly ran out of her hiding spot, only to freeze when seeing no one. A finger slowly trailed up her spine while a voice whispered from behind, "Tag! Your it~!", which made the kunoichi jump and quickly flip around.

"That's pretty dangerous, Yumiko. You could have cut me, ya know!" Killua huffed, grabbing her wrist when the fan was close to his face; squeezing it hard enough to make her drop it.

Yumiko found a growl leaving her lips since Killua was grinning at her, and it angered her since he was acting like this was just some sort of game! She aimed a kick at his knee before twisting her body, managing to break free from his grip where she jumped away from him.

"Idiot! What do you think you're doing?!" Killua uttered out in annoyance, easily dodging the shuriken's she threw at him. "We shouldn't be fighting! Besides, you know you don't stand a chance against me…."

These words made her flinch, knowing he had a point. Despite being a year older than Killua, he out ranked her in both experience and strength. "Maybe…But I'm going to make you regret taking my loved ones from me. Even if it kills me too…!"

Before she could rush at Killua who seemed stunned by her words, Yumiko felt a sharp pain on the back of her neck that caused the girl to lose her balance. The kunoichi struggled to remain conscious, yet her surroundings were growing hazy. And the last thing she heard before darkness consumed her, was Killua yelling out her name.

* * *

Grey eyes slowly fluttered open, and Yumiko winced from the bright light filtering in from the white curtains. She felt disoriented, having no idea where she was or why her neck hurt and eyes slightly stung.

The sound of a door unlocking made her cautiously sit up on the soft bed where she was laying, and she blinked when Killua entered; the concern that had been on his face being replaced with a smile of relief.

"Good! Your finally awake!" he breathed out, moving to sit next to her on the bed where a light scowl slowly crept onto his features. "Damn Illumi had to knock you out. Sure you were out of control, but he had no right to touch you…."

Yumiko cocked her head wondering what Killua meant by her being 'out of control'? Almost as if a TV had been placed inside her head, flashes of imagery started to rush through her mind, and this made her wince. A hand moved to hold her throbbing head when seeing the bloodbath of her home, the bodies of her family, Chieko being killed right in front of her….

Eyes shooting wide in realization, Yumiko made a run for the door. Just as she tried to turn the knob, arms wrapped around her, pulling her close to a lean, yet strong torso that held firmly onto her struggling form.

"Calm down, Yumiko…!"

"H-how can I be calm when I'm in the room with the monster who killed my family…?!"

Killua flinched at this word. Monster? How could _his_ Yumiko call him such a hurtful word? "You don't mean that…."

Yumiko stopped squirming when hearing the clear hurt in his voice. Her head lowered where her locks hid her face that looked conflicted. She hated knowing she was probably causing him pain, but they could never go back to what they once had. "I do…."

His grip tightened on her, making Yumiko let out a small whimper since it felt like he was trying to break every bone in her body.

"You. Don't. Mean. That." Killua repeated, the sudden smile on his lips looking completely unhinged. "Say that you don't."

The raven haired girl gritted her teeth to hold back screaming from the pain, tears welling up in the corners of her eyes. "I-I didn't…mean what I said…."

Killua hummed happily as he released his hold on the kunoichi, not really noticing how much he had shaken her up as he gently patted at the top of her head. "You shouldn't kid around like that."

He frowned when noticing that Yumiko's shirt had some blood on it and clicked his tongue. "I bet your so irritable 'cause your covered in blood. You always got annoyed whenever your stupid clothes got dirty," he mused, pushing her back over toward the bed and helping her into it. "Rest while I go find you something to change into."

Yumiko didn't say anything, staring lifelessly up at the ceiling until she heard Killua leave and the door click, showing he had locked her in the rather beautiful pale blue room.

 _Everyone_ … _I'm so sorry_. _If only I had gotten there faster_ , _maybe I could have stopped him_ _some how_ Yumiko thought, curling up into a ball while silent tears leaked from her eyes.

* * *

Every time Killua entered her room, Yumiko chose to ignore him, not caring how much she angered the handsome teen by her cold actions.

All of the gifts he showered her with, the beautiful clothes he brought her to wear, the compliments he gave her, nothing he did would make her smile, no matter how much he expected it would.

A few times Yumiko had even tried to escape, yet had always been caught before she could even reach the Testing Gate, and this would often cause Killua to chain her to the bed in fury; leaving her without food or water for days. His way of punishment.

Finally seeming to get fed up with her cold treatment, Killua had tossed her down in his basement, that appeared more like some medieval torture chamber, telling her in anger she could remain down here until she started behaving like her 'normal' self again.

This thought caused a deep frown to from on her chapped lips, and she once again proceeded to jab her kunai into the wall. If anyone here wasn't 'normal' it was him.

 _I guess its understandable considering what sort of family Killua comes from, but he never seemed insane like the others_ Yumiko thought regrettably. _It always seemed like we were similar in a way, growing up in such dangerous settings and trying to become something more than what was expected of us, but I guess I was wrong_ ….

"…Yumiko? What exactly do you think you're doing…?"

A small sliver of fear ran down the girls spine at the chilling voice, having not even heard the door opening or his footsteps. And why was he even back this soon? The only reason she had decided to try and risk escaping was because he was going to visit Gon and the others….

She let out a small cry when he was gripping onto her hand that held the kunai, digging his inhumanly long nails into her skin to force her to let go. Small drops of blood fell to the stone floor as she was yanked up, and her arms were roughly pinned behind her back.

"Can't believe you managed to hide that from me. Guess I should have searched you more thoroughly," Killua muttered, his eyes narrowed into slits. "After everything I've done for you, why do you keep trying to leave me like this…?!"

A small derisive laugh left Yumiko's pale lips while she turned to glare back at him. "Yes, you've truly been an amazing friend, Killua. Killing people I care about and then treating me like some sort of prisoner is what any girl would want…!"

Killua had released her arms to slam her up against the wall, and Yumiko didn't halt her glare as she stared up into his furious orbs. She still found it hard to believe someone she had once teased for being shorter than her now slightly towered over her, and he would probably continue to increase in height, too….

She almost wondered if maybe she had angered him enough that he was going to use those extended nails of his to rip into her throat when they touched her soft flesh, and he smiled devilishly.

"So that's how it is, huh? Maybe I just haven't proven to you just how deeply I care about you; how far I'd go," Killua said in a hushed tone. "I was going to leave it as a surprise, but I've been taking more dangerous assignments lately to improve my own skills. It might take me a while, but I'll eventually be strong enough to kill every member of my family…."

Yumiko's orbs grew large since she couldn't believe what she was hearing. She had once eavesdropped on him mentioning to Gon about turning over his family, but assassinating them? "Are you trying to tell me…that you could even kill little Alluka…?"

Killua seemed to almost hesitate with his answer, but he nodded and rubbed at her cheek. "I love Alluka, but I love you more, Yumiko…That's why I'm willing to erase everyone in our lives where it'll be just the two of us…."

"You're…insane…." Yumiko whispered out, still staring at Killua with wide disbelieving eyes.

"Hey, Yumiko? You remember when we first kissed, you were rubbing my cheek just like this before you leaned into me ever…so…slowly," Killua murmured, letting his breath tickle her lips for a moment before he captured them.

The kiss was nothing like hers, though. Yumiko's had been soft and more on the awkward side since she wasn't exactly sure how to move her lips. Killua's on the other hand was rough, and filled with a desire that startled her.

His hands rubbed at Yumiko's arms while he sucked on her lips, wishing she would kiss him back, but he was happy just being able to taste her. Their first kiss he had frozen on the spot from shock and maybe a bit of fear since he couldn't fully comprehend all of the emotions that were wrestling inside of him. He had never felt such impulses toward someone before, that was why he had gone to a corner of the room, ignoring Yumiko's playful teasing about having never realized how shy he was, while he tried to come to terms with what he was experiencing.

He had admittedly disliked Yumiko at first before eventually coming to see her as a friend the same way he did Gon. But after everything they had gone through, his feelings toward Yumiko grew stronger, and it had greatly confused him since this was different from how he felt toward Gon.

It was true he often got jealous whenever Gon seemed to befriend someone else, yet he had never wanted to murder them the way he did when Yumiko seemed to bond or would get a small crush on someone.

At first, he figured maybe he had developed a simple crush himself that would fade with time. Yet hearing her confess her love after the kiss in such a genuine voice he never believed he'd hear from anyone, was what made him realize maybe, they were destined to be together after all. The kunoichi was meant to be his, and he would make sure nothing could take her from him even if it drove him into becoming what he had once tried to escape from….

"Kil-umph!" Yumiko tried to say since she needed a breath of air, only for him to silence her when his tongue was shoved into her mouth.

The back of her neck heated up from the strange sensation of the warm, fleshy organ rubbing all over her cavern. And she was finding it difficult to hold back a moan when his tongue was trailing over hers, trying to coax it into dancing with his own.

Feeling his hands slowly trailing up her sides and towered her chest caused the teenager to squeak and push him away; pants leaving her form while she placed a hand on her racing heart.

"You liked that, didn't you? The blood wouldn't be racing to your face otherwise~" Killua mentioned slyly.

"D-don't be stupid! You just surprised me is all!" Yumiko expressed with furrowed brows before averting her eyes to the side.

Killua just chuckled, gripping onto her chin and turning it so she'd be facing him once more. "Liar~ But I guess I shouldn't be treating you like that. You need to be punished after your little stunt…."

Yumiko chewed on the inside of her mouth knowing he'd probably end up torturing her worse if she said anything or did try to fight back, allowing the white haired male to pull her over to some chains that hung from the ceiling and cuff her wrists into them.

"…Killua? When you went to see our friends, how were they doing?" Yumiko asked softly.

Killua rose a brow before picking up the dagger on the ground and casually tossing it up and down in the air. "They're still in shock that your entire clan was massacred along with you. I keep having to remind them that they're no match for your 'killer' or they'd be trying to hunt them down, and that wouldn't be good…."

"Earlier you said you'd erase everyone in our lives, please tell me you didn't mean Gon and the others, too…?"

"Of course I don't _want_ to hurt our friends! I still care about them…but if they do start looking into your family's murder and discover what really happened, I can't guarantee anything…." Killua said, a shadow forming over his eyes.

"Killua…if I find out you hurt any of them, then the love I once felt for you will completely disappear. And I'll find a way to kill myself even if you lock me in the tiniest room in chains that I can't break free from so you'll be forced to be all alone…."

"You…can't be serious?" Killua murmured out with parted lips. He let out a growl, pressing the dagger against her throat to make it bleed some, but she continued to keep up that defiant look, this making him grind his teeth. "Fine. I won't ever hurt them…But, you have to _swear_ to me you'll stop trying to escape, even if our friends do learn you're here, you won't leave with them. And you'll do whatever I ask of you…."

"…I swear."

Her eyes shut tight when Killua lifted up her chin with the end of the kunai, licking up the blood on her throat. Only when she felt him pulling up the plain yellow dress she had on and felt the cool tip of the blade against her thigh, did they shoot back open.

"…What do you think you're doing…?"

"Leaving a mark so you'll remember who you belong to," Killua said lowly with a smirk. "I should have done this sooner. Maybe then, you wouldn't have been so troublesome."

"Y-you wouldn't?!" Yumiko gasped out, a look of fear in her eyes. During Trick Tower, she had fought against a psychotic child who ended up placing his Nen inside of her. The kid had been able to enter inside of her dreams even when they were miles apart where he had tortured her in various ways. The worst had been when he carved his name into her arm like she was some sort of toy, and the experience had greatly shaken her up. And Killua was actually going to do the same thing to her even after knowing this?!

"Q-quit squirming around or I'll mess up and end up hurting you worse!" Killua grunted out before digging the kunai into her flesh and forming a small 'K'.

"P-please…stop…!" Yumiko begged, tears from the pain cascading down her cheeks; letting out a small scream when he started to carve the second letter of his name into her thigh as it burned even worse than his first cut had.

"Shh. I'm nearly done." Killua cooed out, admiring his handy-work for a moment before he finished with an 'l'. He licked up the blood that was trailing from her thigh down her leg, finding himself enjoying the taste of her red liquid almost as much as he did her lips.

He let her dress fall back down, moving in front of her as he wiped the tears off of her soft cheeks. "You know I don't like seeing you upset like this, Yumiko, but I told you that you had to be punished…Just remember I'll write out the rest of my name if you misbehave again."

He placed the kunai in the pockets of the black pants he wore before grinning. "I'll be gone for two days, but I know you'll be fine. And if your still in those chains when I get back, I have something nice for you~"

Placing a chaste kiss on her lips before heading for the basement stairs, Killua flipped around with a passionate look in his gaze that would have once made Yumiko blush. "I love you, Yumiko."

Not receiving an answer, the assassin frowned. "Did you hear me?"

"I…I love you, too…." Yumiko replied back in a cracked voice, her head lowered where she wouldn't have to look at him.

Killua let out a satisfied hum, smiling and giving her a little wave before leaving; turning out the light on her and leaving her in complete darkness.

Ninjas were meant to live their lives in the shadows, yet she had at least been able to see the sun every now and then…Now, it seemed she'd be trapped in this mansion, in this darkness, forever….


End file.
